Automated methods to test connectedness and quantify indirectness of evidence in network meta-analysis.

Network meta-analysis compares multiple treatments from studies that form a connected network of evidence. However, for complex networks, it is not easy to see if the network is connected. We use simple techniques from graph theory to test the connectedness of evidence networks in network meta-analysis.

Simultaneous synthesis of treatment effects and mapping to a common scale: an alternative to standardisation.

Objective: Trials often may report several similar outcomes measured on different test instruments. We explored a method for synthesising treatment effect information both within and between trials and for reporting treatment effects on a common scale as an alternative to standardisation

Study Design: We applied a procedure that simultaneously estimates a pooled treatment effect and the "mapping" ratios between the treatment effects on test instruments in a connected network. Standardised and non-standardised treatment effects were compared.

A polysaccharide extract of mulberry leaf ameliorates hepatic glucose metabolism and insulin signaling in rats with type 2 diabetes induced by high fat-diet and streptozotocin.

Mulberry leaf is a traditional medicine used to treat diabetes in the clinic. The aim of this study was to determine the mechanisms by which mulberry leaf polysaccharide (MLPII), improves hepatic glucose metabolism and insulin resistance in rats with type 2 diabetes induced by high fat and streptozotocin (STZ). MLPII was administered for 6 weeks after establishment of type 2 diabetes in Wistar rats.

Anti-diabetic effect of mulberry leaf polysaccharide by inhibiting pancreatic islet cell apoptosis and ameliorating insulin secretory capacity in diabetic rats.

Diabetes mellitus is a clinically complex disease characterized by chronic hyperglycemia with metabolic disturbances. In this study, we investigated the effect of mulberry leaf polysaccharide (MLPII) on pancreatic islet cell apoptosis and insulin secretory function in diabetic rats induced by a high fat diet and streptozotocin. Our results showed that MLPII treatment inhibited pancreatic islet cell apoptosis and ameliorated insulin secretory capacity of pancreatic β-cells in diabetic rats.

Simultaneous multioutcome synthesis and mapping of treatment effects to a common scale.

Objectives: A new method is presented for both synthesizing treatment effects on multiple outcomes subject to measurement error and estimating coherent mapping coefficients between all outcomes. It can be applied to sets of trials reporting different combinations of patient- or clinician-reported outcomes, including both disease-specific measures and generic health-related quality-of-life measures. It is underpinned by a structural equation model that includes measurement error and latent common treatment effect factor.

Evidence synthesis for decision making 4: inconsistency in networks of evidence based on randomized controlled trials.

Inconsistency can be thought of as a conflict between "direct" evidence on a comparison between treatments B and C and "indirect" evidence gained from AC and AB trials. Like heterogeneity, inconsistency is caused by effect modifiers and specifically by an imbalance in the distribution of effect modifiers in the direct and indirect evidence. Defining inconsistency as a property of loops of evidence, the relation between inconsistency and heterogeneity and the difficulties created by multiarm trials are described.

Which health-related quality-of-life outcome when planning randomized trials: disease-specific or generic, or both? A common factor model.

The primary outcomes in trials are usually disease-specific measures (DSMs) designed to be responsive to changes in the condition caused by treatment. For purposes of cost-effectiveness analysis, treatment effects on the DSM are often "mapped" into treatment effects on a generic health-related quality-of-life (QOL) scale, such as EuroQol five-dimensional questionnaire. Trialists have the option of including generic QOL measures as trial outcomes.

Mapping from disease-specific to generic health-related quality-of-life scales: a common factor model.

Objectives: To develop a coherent method for estimating mappings between treatment effects on disease-specific measurement (DSM) instruments and generic health-related quality-of-life (QOL) measures, when both are subject to measurement errors.

Methods: We identified three properties that must be satisfied for mappings to be logically coherent: invertability, transitivity, and invariance to linear transformation. Of the common regressions, ordinary least squares (OLS), geometric mean (GM), and orthogonal regression, only GM has all these properties, and then only in special cases.

Automating network meta-analysis.

Mixed treatment comparison (MTC) (also called network meta-analysis) is an extension of traditional meta-analysis to allow the simultaneous pooling of data from clinical trials comparing more than two treatment options. Typically, MTCs are performed using general-purpose Markov chain Monte Carlo software such as WinBUGS, requiring a model and data to be specified using a specific syntax. It would be preferable if, for the most common cases, both could be derived from a well-structured data file that can be easily checked for errors.

Extending methods for investigating the relationship between treatment effect and baseline risk from pairwise meta-analysis to network meta-analysis.

Baseline risk is a proxy for unmeasured but important patient-level characteristics, which may be modifiers of treatment effect, and is a potential source of heterogeneity in meta-analysis. Models adjusting for baseline risk have been developed for pairwise meta-analysis using the observed event rate in the placebo arm and taking into account the measurement error in the covariate to ensure that an unbiased estimate of the relationship is obtained. Our objective is to extend these methods to network meta-analysis where it is of interest to adjust for baseline imbalances in the non-intervention group event rate to reduce both heterogeneity and possibly inconsistency.

Effects of electromagnetic radiation on spatial memory and synapses in rat hippocampal CA1.

In this study, we investigated the effects of mobile phone radiation on spatial learning, reference memory, and morphology in related brain regions. After the near-field radiation (0.52-1.

Linear inference for mixed treatment comparison meta-analysis: A two-stage approach.

Mixed treatment comparisons (MTC) meta-analysis synthesises comparative evidence on multiple treatments or other interventions from a collection of randomised controlled trials (RCT) available in a research area, while still respecting the randomisation structure in RCTs. This paper sets out to examine the properties of MTC estimates and elucidate the concept of consistency between direct and indirect evidence in MTC networks. We decompose MTC synthesis into two stages.

[Effects of 2000 μW/cm2; electromagnetic radiation on expression of immunoreactive protein and mRNA of NMDA receptor 2A subunit in rats hippocampus].

Aim: To evaluate the effects of electromagnetic irradiation of 2000 μW/cm(2); exposure on mRNA and protein expression levels of immunoreactive protein and mRNA of NMDA receptor 2A subunit in rats hippocampal, and to explore the mechanism of electromagnetic irradiation induced learning and memory impairment.

Methods: Rats were randomly divided into normal control group, sham-radiated group, and 1 h/d, 2 h/d, and 3 h/d radiation groups. The rats in the radiation groups were fixed after microwave exposure of 2000 μW/cm(2);, then their learning and memory abilities were tested by Morris water maze experiment, the change of NR2A protein in hippocampal neurons of each group of rats were measured with immunohistochmistry and Western blot techniques, and the expression of NR2A mRNA in hippocampus were determined by RT-PCR.

Colonization of Morus alba L. by the plant-growth-promoting and antagonistic bacterium Burkholderia cepacia strain Lu10-1.

Background: Anthracnose, caused by Colletotrichum dematium, is a serious threat to the production and quality of mulberry leaves in susceptible varieties. Control of the disease has been a major problem in mulberry cultivation. Some strains of Burkholderia cepacia were reported to be useful antagonists of plant pests and could increase the yields of several crop plants.

Modeling between-trial variance structure in mixed treatment comparisons.

In mixed treatment comparison (MTC) meta-analysis, modeling the heterogeneity in between-trial variances across studies is a difficult problem because of the constraints on the variances inherited from the MTC structure. Starting from a consistent Bayesian hierarchical model for the mean treatment effects, we represent the variance configuration by a set of triangle inequalities on the standard deviations. We take the separation strategy (Barnard and others, 2000) to specify prior distributions for standard deviations and correlations separately.

Multiparameter evidence synthesis in epidemiology and medical decision-making.

Meta-analysis has been well-established for many years, but has been largely confined to pooling evidence on pair-wise contrasts. Broader forms of synthesis have also been described, apparently re-invented in disparate fields, each time taking different computational approaches. The potential value of Bayesian estimation of a joint posterior parameter distribution and simultaneously sampling from it for decision analysis has also been appreciated.

[Identification and colonization of an antagonistic endophytic Burkholderia cepacia Lu10-1 isolated from mulberry].

Objective: To identify and colonize an antagonistic bacterium, Lu10-1, isolated from the healthy mulberry.

Methods: Strain Lu10-1 was identified based on the analysis of its 16S rRNA gene sequence homology, the physiological and biochemical characteristics, and the recA gene sequence comparison. A spontaneous Lu10-1 mutant tolerant to rifampicin and ampicillin were isolated by gradually increasing the concentration of the two antibiotics.

Biological control against bacterial wilt and colonization of mulberry by an endophytic Bacillus subtilis strain.

Forty-five bacterial isolates were collected from surface-sterilized leaves of mulberry (Morus alba L.). By screening their antagonistic activities against Ralstonia solanacearum in vitro, four isolates showed a remarkable inhibitory effect.

Mixed comparison of stroke prevention treatments in individuals with nonrheumatic atrial fibrillation.

Background: We aimed to identify different stroke prevention treatments for atrial fibrillation assessed in randomized controlled trials and to compare them within a single evidence synthesis framework.

Methods: We updated the Cochrane review on anticoagulants and antiplatelet therapy for nonrheumatic atrial fibrillation to include randomized controlled trials published between January 2000 and March 2005 identified via the CENTRAL database and MEDLINE. A mixed-treatment comparison method was used to combine direct within-trial, between-treatment comparisons with indirect trial evidence while maintaining randomization.

Bayesian methods for evidence synthesis in cost-effectiveness analysis.

Recently, health systems internationally have begun to use cost-effectiveness research as formal inputs into decisions about which interventions and programmes should be funded from collective resources. This process has raised some important methodological questions for this area of research. This paper considers one set of issues related to the synthesis of effectiveness evidence for use in decision-analytic cost-effectiveness (CE) models, namely the need for the synthesis of all sources of available evidence, although these may not 'fit neatly' into a CE model.

Sensitivity analysis for informative censoring in parametric survival models.

Most statistical methods for censored survival data assume there is no dependence between the lifetime and censoring mechanisms, an assumption which is often doubtful in practice. In this paper we study a parametric model which allows for dependence in terms of a parameter delta and a bias function B(t, theta). We propose a sensitivity analysis on the estimate of the parameter of interest for small values of delta.